Pharmacology

Question 1

1. Which one of the following statements regarding paracetamol Is true?
   a. It is excreted unchanged by the kidney
   b. The maximum recommended daily dose in an adult in 4g
   c. It is not antipyretic
   d. It inhibits coughing
   e. It should not be given in patients allergic to aspirin

Answer 1

 B. The maximum recommended daily dose in an adult in 4g
 Paracetamol is metabolised in the liver, is antipyretic, and does not inhibit coughing.

Question 2

2. Which one of the following drugs cannot be used in pregnancy?
   a. Tetracycline
   b. Paracetamol
   c. Nystatin
   d. Lidocaine
   e. Penicillin

Answer 2

 A. Tetracycline
 Tetracycline affects tooth and bone formation. Particularly relevant to dentistry is the brown lines which appear on teeth that were developing during the period of administration of tetracycline.

Question 3

3. Which one of the following is not a recognised effect of orally administered steroids?
   a. Weight loss
   b. Osteoporosis
   c. Hyperglycaemia
   d. Mental disturbances
   e. Immunosuppression

Answer 3

 A. Weight loss
 Steroids cause Cushingoid effects leading to weight gain, osteoporosis, diabetes and immunosuppression.

Question 4

4. Which one of the following statements is not true?
   a. Carbamazepine leads to abnormal liver function tests.
   b. Flumazenil is a benzodiazepine antagonist
   c. Benzodiazepines are commonly used anxiolytics
   d. Benzodiazepines are used in the treatment of epilepsy
   e. Carbamazepine is a benzodiazepine

Answer 4

 E. Carbamazepine is a benzodiazepine
 Carbamazepine is a drug used for trigeminal neuralgia and epilepsy, however it is not a benzodiazepine. It has side effects which include abnormal liver function tests and bone marrow suppression. Benzodiazepines act on the central nervous system and can have hypnotic, anxiolytic, anticonvulsant and sedative effects. Flumazenil is the reversal agent for midazolam and therefore a benzodiazepine antagonist.

Question 5

5. Which one of the following statements is correct about local anaesthesia?
   a. The most commonly used local anaesthetic in dental surgeries is 0.2% lidocaine with 1:80 000 adrenaline
   b. Lidocaine must be stored below 5*C
   c. Lidocaine has a longer lasting effect that bupivacaine
   d. Lidocaine without adrenaline has a longer lasting effect that lidocaine with adrenaline
   e. 3% prilocaine with 0.03% IU/ml felypressin is a commonly used dental anaesthetic

Answer 5

 E. 3% prilocaine with 0.03% IU/ml felypressin is a commonly used dental anaesthetic
 Prilocaine is more commonly known by its trade name Citanest. Lidocaine is normally used as a 2% solution and adrenaline causes the vasoconstriction, leading to increased anaesthesia.

Question 6

6. Which one of the following statements is correct about lidocaine?
   a. A 2.2ml cartridge of 2% lidocaine contains 4.4mg of lidocaine
   b. Lidocaine and prilocaine are esters
   c. Esters are more likely to cause an allergic reaction that amides
   d. Amide local anaesthetics are metabolised by the liver
   e. Prilocaine is more toxic than lidocaine

Answer 6

 C. Esters are more likely to cause an allergic reaction than amides
 The 2.2ml cartridge contains 44mg of lidocaine. Both lidocaine and prilocaine are amides and therefore are less likely to cause an allergic reaction. Lidocaine is a much more toxic drug than prilocaine.

Question 7

7. Which one of the following is not an anti-fungal drug?
   a. Miconazole
   b. Fluconazole
   c. Aciclovir
   d. Nystatin
   e. Itraconazole

Answer 7

 C. Aciclovir
 Aciclovir is an anti-viral drug, commonly used topically for herpes simplex. It can also be used more effectively systemically.

Question 8

8. Regarding penicillin, which one of the following statements is incorrect?
   a. Penicillin is the antibiotic of choice for anaerobic infections.
   b. It works by interfering with bacterial cell wall synthesis.
   c. It is bactericidal.
   d. It is antagonist to tetracycline
   e. It frequently causes allergic reactions.

Answer 8

 A. Penicillin is the antibiotic of choice for anaerobic infections.
 Penicillins are a bactericidal group of antibiotics. Their mode of action is to inhibit the cross linking of mucopeptides in cell walls and therefore prevent cell wall synthesis. The drug of choice for anaerobic infections is metronidazole

Question 9

9. Which one of the following drugs can be prescribed safely in pregnancy?
   a. Metronidazole
   b. Paracetamol
   c. Prilocaine
   d. Miconazole
   e. Methotrexate

Answer 9

 B. Paracetamol
 Methotrexate can be used to produce an abortion in the early stages of pregnancy. Prilocaine can induce labour, especially when combined with felypressin.

Question 10

10. Which one of the following drugs does not induce gingival hyperplasia?
    a. Nifedipine
    b. Carbamazepine
    c. Phenytoin
    d. Diltiazem
    e. Ciclosporin

Answer 10

 B. Carbamazepine
 Nifedipine and diltiazem are calcium channel blockers, phenytoin is an anti-epileptic and ciclosporin is an immunosuppressant. They all induce gingival hyperplasia.

Question 11

11. Patients who take warfarin should always:
    a. Carry a purple warning card
    b. Have a therapeutic range of international normalised ration (INR) between 2 and 3
    c. Stop all anti-coagulants 3 days prior to tooth extractions
    d. Have their blood regularly monitored to measure their INR
    e. Wear a MedicAlert bracelet

Answer 11

 D. Have their blood regularly monitored to measure their INR.
 The warning card is a yellow card, and they do not need to wear a MedicAlert bracelet. Their doctor decides the appropriate level of INR, which may be as must as 4.5 for patients who have had a valve replacement. They may not need to stop their anticoagulants for simple extractions if their INR is below 3.5 we should be able to cope with this level of haemorrhage.

Question 12

12. Which of the following statements regarding tetracyclines is true?
    a. They are narrow spectrum antibiotics
    b. They are absorbed better when taken with milk
    c. They may be used as a mouthwash in a dose of 45mg dissolved in a little water and held in the mouth.
    d. They cause intrinsic staining of teeth.
    e. They cause extrinsic staining of teeth.

Answer 12

 D. Tetracyclines should not be given in pregnancy nor in patients who are under 12 years of age. A 250mg tetracycline capsule can be used as a mouthwash to prevent or treat infected oral ulceration.

Question 13

13. Which one of the following is a sign or symptom of lidocaine overdose?
    a. Light headedness
    b. Tachycardia
    c. Rash
    d. Hypertension
    e. Hyperventilation

Answer 13

 A. Light headedness
 Signs and symptoms of lidocaine overdose are: respiratory depression, hypotension, bradycardia, confusion, convulsions and light headedness.

Question 14

14. Which one of the following does not always need to be included on a prescription?
    a. The prescriber’s signature
    b. The date of the prescription
    c. The dose of the drug in words
    d. The name and address of the prescriber
    e. The address of the patient

Answer 14

 C. The dose of the drug in words
 Only if the drug being prescribed is a controlled drug does the dose of the drugs have to be written in words.

Question 15

15. Lidocaine works by blocking which one of the of the following channels?
    a. Calcium channels
    b. Sodium channels
    c. Potassium channels
    d. Hydrogen channels
    e. Chloride channel

Answer 15

 B. Sodium channels
 Lidocaine works by blocking sodium channels and prevents depolarisation of the nerve membranes as it stabilised the membranes.

Question 16

16. Which one of the following statements regarding aspirin is false?
    a. It is a non-steroidal anti-inflammatory drug (NSAID)
    b. It prevents the synthesis of prostaglandin E2.
    c. It has anti-pyretic properties.
    d. It is commonly used analgesic for children.
    e. It may cause gastric mucosal irritation and bleeding.

Answer 16

 D. It is commonly used analgesic for children
 Aspirin is an NSAID which prevents the synthesis of prostaglandin E2. It has anti-pyretic properties because of its action in the hypothalamus and should be avoided in children due to possibility of Reye’s syndrome.

Question 17

17. Which one of the following interacts with warfarin to alter the patient’s INR?
    a. Fluconazole
    b. Vitamin K
    c. Metronidazole
    d. Erythromycin
    e. Aspirin

Answer 17

 B. Vitamin K
 Fluconazole, metronidazole and erythromycin potentiate warfarin’s action. Vitamin K interacts with warfarin but causes a lowering of the INR. Aspirin does not affect the INR as it does not interfere with the clotting cascade, only the function of the platelets.

Question 18

18. Which one of the following drugs and doses for the treatment of atypical facial pain is not correct?
    a. Dothiepin 75mg nocte
    b. Amitriptyline 25mg daily
    c. Fluoxetine 20mg daily
    d. Flumazenil 20mg daily
    e. Nortriptyline 25mg daily

Answer 18

 D. Flumazenil 20mg daily
 All of the above except D. are used for the treatment of atypical facial pain. Flumazenil is a reversal agent for midazolam and therefore is not used for the treatment of atypical facial pain.

Question 19

19. Which one of the following is not an NSAID?
    a. Aspirin
    b. Ibuprofen
    c. Indometacin
    d. Naproxen
    e. Paracetamol

Answer 19

 E. Paracetamol
 All of the above except paracetamol are NSAIDs. Indometacin and naproxen are especially used in rheumatoid arthritis.

Question 20

20. Which one of the following is a mechanism by which erythromycin works?
    a. It blocks protein synthesis at the 30S ribosomal unit
    b. It blocks protein synthesis at the 50S ribosomal unit
    c. It blocks mRNA synthesis
    d. It blocks peptidoglycan synthesis
    e. It blocks cell wall synthesis

Answer 20

 B. It blocks protein synthesis at the 50S ribosomal unit
 Gentamicin works at the 30S subunit, rifampicin block mRNA synthesis, vancomycin classically blocks peptidoglycan synthesis and penicillin blocks cell wall synthesis.

Question 21

21. Which one of the following antibiotics can cause pseudomembranous colitis?
    a. Amoxicillin
    b. Erythromycin
    c. Clindamycin
    d. Metronidazole
    e. Chloramphenicol

Answer 21

 C. Clindamycin
 Clindamycin causes the death of many commensal organisms in the colon and leads to overgrowth of less favourable organisms causing pseudomembranous colitis, which has a high mortality.

Question 22

22. Which one of the following clotting factors is not affected by warfarin?
    a. II
    b. VII
    c. VIII
    d. XI
    e. X

Answer 22

 C. VIII
 Warfarin affects the extrinsic clotting pathway and prolongs the prothrombin time. It increases bleeding and is teratogenic.

Question 23

23. Which one of the following commonly prescribed antibiotics produces a disulfiram-like reaction on ingestion of alcohol?
    a. Amoxicillin
    b. Erythromycin
    c. Clindamycin
    d. Metronidazole
    e. Chloramphenicol

Answer 23

 D. Metronidazole
 Metronidazole has the classic disulfiram-like reaction with alcohol. Patients should be always advised to avoid alcohol when taking this drug.

Question 24

24. Which of the following drug-side effect combinations is correct?
    a. Vancomycin – Red man syndrome
    b. Amoxicillin – pseudomembranous colitis
    c. Propranolol – gingival hyperplasia
    d. Paracetamol – Reye’s syndrome
    e. Erythromycin – tooth staining

Answer 24

 A. Vancomycin – Red man syndrome
 Clindamycin causes pseudomembranous colitis; nifedipine or diltiazem are the anti-hypertensives which cause gingival hyperplasia; aspirin, not paracetamol causes Reye’s syndrome; and tetracyclines cause tooth staining.

Question 25

25. Which is the most important drug to be administered in an Addisonian crisis? a. Adrenaline b. Hydrocortisone sodium succinate c. Prednisolone d. Chlorphenamine e. Flumazenil

Answer 25

 B. Hydrocortisone sodium succinate  A patient having an Addisonian crisis has a lack of corticosteroids in their circulation, which leads to collapse. Intravenous hydrocortisone sodium succinate is the drug of choice to help rectify the situation. Prednisolone is a steroid also, however it is given orally and takes longer to act. Therefore it is ineffectual in an emergency situation.

Question 26

26. Which one of the following is not a side effect of an excess of opioid treatment? a. Respiratory depression b. Constipation c. Addiction d. Hallucination e. Dilated pupils

Answer 26

 E. Dilated pupils  Miosis or pinpoint pupils is one of the signs of opiate misuse or overdose. All of the other options are correct.

Question 27

27. Which one of the following drugs should not be given to asthmatic people? a. Metronidazole b. Amoxicillin c. Ibuprofen d. Captopril e. Paracetamol

Answer 27

 C. Ibuprofen  Ibuprofen is contraindicated in asthma as it causes bronchoconstriction and can precipitate an asthma attack.

Question 28

28. Which one of the following statements regarding paracetamol is incorrect? a. It is an anti-pyretic b. An overdose is treated by N-acetylcysteine c. It is locally acting d. It is hepatotoxic in overdose e. It Is prescribed in doses of between 500mg and 1g four times daily.

Answer 28

C. It is locally acting D. Paracetamol has a systemic action, acts centrally and has an anti-pyretic action. An overdose is hepatotoxic and is treated by N-acetylcysteine.

Question 29

29. Which one of the following doses of adrenaline in the treatment of anaphylaxis is correct? a. Adrenaline 0.5ml of 1:100 intramuscularly b. Adrenaline 5ml of 1:100 intramuscularly c. Adrenaline 0.5ml of 1:1000 intramuscularly d. Adrenaline 5ml of 1:1000 intramuscularly e. Adrenaline 0.5ml of 1: 10 000 intramuscularly

Answer 29

 C. 0.5ml of 1:1000 intramuscularly

Question 30

30. Which one of the following causes a dry mouth? a. Adrenaline b. Atropine c. Amoxicillin d. Anti-malarials e. Angiotensin-converting enzyme (ACE) inhibitors

Answer 30

 B. Atropine  Atropine is an antimuscarinic drug which leads to the decreased salivary outflow and the dry mouth.

Question 31

31. The most effective drug in the treatment of Parkinson’s disease is: a. Levodopa b. Sulfasalazine c. Metoclopramide d. Bactroban e. Clopidogrel

Answer 31

 A. Levodopa  Parkinson’s disease belongs to a group of conditions called movement disorders. It is characterised by muscle rigidity, tremor, a lowing or physical movement (bradycardia) and, in extreme cases, a loss of physical movement (akinesia). The primary symptoms are the result of decr stimulation of the motor cortex by the basal ganglia, usually caused by the insufficient formation and cation of dopamine, which is produced in the dopaminergic neurones of the brain. Secondary symptoms may include high-level cognitive dysfunction and subtle language problems. Parkinson’s disease is both chronic and progressive and is the most common cause of chronic progressive parkinsonism, a term which refers to the syndrome of tremor, rigidity, bradykinesia and postural instability. Parkinson’s disease also called ‘primary parkinsonism’ or ‘idiopathic Parkinson’s disease’ (having no known cause although many genetic mutations associated w Parkinson’s disease have since been discovered.) Although many forms of Parkinsonism are idiopathic, secondary instances may result from toxicity most notably of drugs, head trauma, or other medical disorders.

Question 32

32. Penicillin is an effective agent against rapidly growing cells because it: a. Interferes with folinic acid production. b. Inhibits RNA synthesis c. Inhibits DNA synthesis d. Inhibits cell wall synthesis e. Interferes with folate synthesis

Answer 32

 D. Inhibits cell wall synthesis  B-Lactam antibiotics work by inhibiting the formation of peptidoglycan cross-links in the bacterial cell wall. The B-Lactam (functional group) of penicillin binds to the enzyme DD-transpeptidase, which links the peptidoglycan molecules in bacteria, and thus weakens the cell wall of the bacterium (the antibiotic causes cytolysis or death due to osmotic pressure). Also, the build-up of peptidoglycan precursors triggers the activation of bacterial cell wall hydrolases + autolysins, which further digest the bacterium’s existing peptidoglycan. Gram +ve bacteria are called protoplasts when they lose their cell wall. Gram-ve bacteria don’t lose their cell wall completely and are called spheroplasts after tx with penicillin. Penicillin shows a synergistic effect with aminoglycosides, since the inhibition of peptidoglycan synthesis allows aminoglycosides to penetrate the bacterial cell wall more easily, allowing disruption of bacterial protein synthesis within cell.

Question 33

33. Sulphonamides are synergistic bacteriostatic agents because in bacteria they: a. Interfere with folinic acid production b. Inhibit RNA synthesis c. Inhibit DNA synthesis d. Inhibit cell wall synthesis e. Interfere with folate synthesis

Answer 33

 A. Interfere with folinic acid production.  In bacteria, antibacterial sulphonamides act as a competitive inhibitor of the enzyme dihydropteroate synthetase (DHPS).

Question 34

34. Procaine is an: a. Amide b. Ester c. Benzoate d. Hypnotic anxiolytic e. Alkylating agent

Answer 34

 B. Ester  Procaine is a local anaesthetic drug of the amino ester group. Procaine is used less frequently today since more effective (and hypoallergenic) alternatives such as lidocaine are available. Procaine has the advantage of constricting blood vessels, which reduces bleeding, unlike other local anaesthetics such as lidocaine, but without the euphoric and addictive qualities of cocaine. Procaine is metabolised in the plasma by the enzyme pseudocholinesterase though hydrolysis into para-amino benzoic acid (PABA), which is then excreted by the kidneys into the urine. Allergic reactions to procaine are usually in response to procaine itself, but to PABA.

Question 35

35. Metronidazole: a. Interferes with folinic acid production b. Inhibits RNA synthesis c. Inhibits nucleic acid synthesis d. Inhibits cell wall synthesis e. Interferes with folate synthesis

Answer 35

 C. Inhibits nucleic acid synthesis  Metronidazole is a prodrug. It is converted in anaerobic organisms by the redox enzyme pyruvate-ferredoxin oxidoreductase. The nitro group of metronidazole is chemically reduced by ferredoxin and the products are responsible for disrupting the DNA helical structure, thus inhibiting nucleic acid synthesis. Metronidazole is selectively taken up by the anaerobic bacteria and sensitive protozoal organisms because of the ability of these organisms to reduce metronidazole to its active form intracellularly.

Question 36

36. Which topically applied antibiotic can be applied to facial wounds to prevent infection and reduce scarring? a. Penicillin b. Erythromycin c. Chloramphenicol d. Metronidazole e. Fluconazole

Answer 36

 C. Chloramphenicol  Chloramphenicol is frequently applied to facial wounds to reduce infection and prevent scarring.